Dental engine



July 21, 1925. 1,546,480

. C. DENZEL DENTAL ENGINE Filed May 5, 1924 f AME q I I L Z fix 1| h d I 2 72 I T 1 1' @ml 1 z; I v

Patented July 21, 1925.

UNITED STATES,

CARL DENZEL, or FREIBURG, GERMANY.

DENTAL ENGINE.

Application filed May 3, 1924. Serial No. 710,792.

To all whom it may concern" Be it known that I, CARL DENZEL', a citi- Zen of Germany, residing at F reiburg, Germany, have invented certain new and useful Improvements in Dental Engines, of which the following is a specification.

The present invention has reference to an improvement in the well known electrically driven dental engines, which permit of drilling and the like and also of hot-air blowing, a fan being driven by the motor shaft and the air current generated thereby led over heat resistances on its way to the parts under treatment.

In the prior devices of this character the drill shaft as well as the blower are always operated conjointly, which makes for undue wear and tear and unnecessarily high current consumption, inasmuch as the two operations are hardly ever required simul taneously. My invention provides for the employment of a reversible motor and coupling means for alternately coupling-in the drill shaft or the blower shaft, so that always only'the one or the other unit is in operation at the same time.

My invention will best be understood when described in connection with the accompanying drawing, in which Fig. 1 is a more or less diagrammatic vertical section through my improved dental engine; Fig. 2 a cross-section on line AB of Fig. 1; Fig. 3 is a cross section through coupling d of the fan; and Fig. 4 is a cross section through coupling 0.

The letter a denotes the stator member of the motor within which rotates the motor shaft Z), to the lower extremity of which the flexible shaft (not shown here) is secured by a one-way, for instance right-hand, coupling c (Fig. 4). On the upper shaft end is mounted the coupling cl (Fig. 3) for rotation to the left, with which coacts the hub of the fan I The motor housing 9 is subdivided by the partition wall Z and is provided near its upper circun'iferential edge with air intake ports '5 which are spacedly hooded by the overhanging cover member h. To prevent dust and other impurities from being sucked into the housing through these holes i there is provided an air-filter back of them. In the upper chamber is mounted the blower unit, and in the lower the motor proper. The partition wall Z is provided at one side with an aperture r communicating with a funnel-shaped intake m to which is 'connected the air conduit 01 which conveniently ends near the tool end of the flexible drill shaft. A baffle plate 0 extending across the partitionwall Z back of the funnel intake serves to back up the fan driven air to assure its entering the air conduit m, n. Below the fan there is provided'an electric heating unit 7) for warming the fan-entrained air prior to its entering, or its issue from, the conduit m, 71. Obviously, the heating unit may also be arranged at some other point in the air passage, and it may be found especially advantageous to dispose it near the discharge or nozzle end of the tube it, since in this instance on starting the fan there is an immediate issue of warm air, whereas, if the heating unit is placed higher up in the conduit, the cold air in the lower part of the conduit must first be expelled.

To operate the device a reversing switch of any suitable make is used, the wire connections of which are such that upon starting the motor in the direction, right or left as the case may be, for operating the blower, the heating unit is simultaneously cut-in whilst both units, the blower and the heater, are cut-out upon the motor being reversed for operating the flexible tool shaft.

l/Vhat I claim is 1. In a dental engine of the character set and switch means for controlling the operation and direction of rotation of said motor, a tool shaft, a blower, and independent coupling means interposed between said motor and said tool shaft and between said motor and said blower respectively, for selectively coupling said motor to said tool shaft or to said fan according as said motor runs in the one. or the other direction.

2. In a. dental engine of the character set forth, in combination with a reversible motor and switch means therefor, a tooloperating coupling actuated by said motor on operation thereof in one direction, a blower unit, comprising a fan, an air conduit and a heating member, and a fan-operating coupling actuated by said motor on opera tion thereof in the respective other direction.

3. In a dental engine of the character set forth, in combination with a reversible motor and switch mechanism therefor, a flexible drill shaft, a blower unit, and coupling means respectively interposed between said motor and said flexible shaft and between said motor and said: blower unlt forselee tively independently operating said flexible shaft and said blower unit according as said motor rotates in the one orthe'other diree tion said blower unit comprising a fan an v air conduit, and aheat member for heating" the fan-impelled air prior to its reaehingthe I issue end of said conduit, and said heat member o'perable only during the operation of ssa'id'rfan;

A." In an dental engine of the character set; f0rth,' i'n combination, a housingpresentingscreened air-intake ports," a partition walldividing: said housing --into :two superposed ohambers," a reversible motor-including shaft-tin the 'lOW'erehaInber, a blower-in the upper chamber, the upper, end o f v saidmotor shafti extending jnto said uppei'i ehainber, and the lower end of said motor shaft exof said housing, a one-way couplingm-einbe-i 01f this external shaft end, a one-way coupling member on the upper endofsa'id motor shaft for coaetion with said blower, said-two coupling members designed forrespotii' ely alternate operation of saidvblower." I: i H p CARL -DENZELQ t-ion only; said partition wall presentingan 

